Casing shoe



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CASING SHOE Filed Feb. 7, 1928 Sept. 3, 1929.

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Patented Sept. 3, 1929.

UNITED STATES OLIVER A. SEWELL, 0F COWIETA, OKLAHOMA.

CASING SHOE.

Application filed February 7, 1928. Serial No. 252,565.

This invention relates to a casing shoe, the general object of the invention being to so form the shoe that an extension tube of smaller diameter than the casing can be attached to the lower end of the shoe so that the well below the shoe can be of smaller diameter than the rest of the well, with the shoe supporting the extension tube at any suitable point in the well.

Another object of the invention is to make the bore of the shoe of tapered formation so that its upper end will be of the same diameter as the interior diameter of the casing and its lower end of the same diameter as the interior of the extension tube to eliminate projections which would interfere with the passage of the drilling tools.

This invention also consists in certain other features of construction and in the combination and arrangement of the several parts, to be hereinafter fully described, illustrated in the accompanying drawing and specifically pointed out in the appended claims.

In describing my invention in detail, reference will be had to the accompanying drawing which is a sectional view through a well, showing the invention in use.

In this drawing, 1 indicates the casing, 2 the extension tube which is of smaller diameter than the casing and 3 indicates the improved shoe for connecting the tube with the casing. As shown, the bore of the shoe tapers downwardly from its upper end to its lower end and the ends of the shoe are grooved, with the walls of the grooves threaded to receive the threaded ends'of the casing 1 and tube 2. This eliminates shoulders at the junction of the parts, so that there are no obstruetions to the passage of the drilling tools. The exterior of the shoe is of cylindrical shape so that its walls are thicker at its lower end than at its upper end. The shoe is provided with the usual beveled lower end 4 for forming a cutting edge to engage the shoulder 5 formed in the well at the junction of the large part of the well with the reduced lower part thereof so that the lower end of the shoe forms a watertight joint with the shoulder 'to pre vent water or the like passing from the large part of the well into the reduced part thereof. By using this improved shoe, the lower part of the well can be made of smaller diameter than the upper part and the shoe will support the tube from the shoulder at any distance above the bottom of the well, where the formation is such as to afford suitable support for the shoe and the tube. For instance, if the oil sand is fifty feet below a stratum solid enough to hold the pipes and between this stratum and the oil sand, there is thirty feet of cavey shale, then the shoe must be supported by the solid stratum and from this point to the oil sand, the well is reduced in diameter, and a fifty foot length of pipe is threaded to the lower end of the shoe and passes through the reduced part of the well and is supported from the shoe, as shown in the drawing.

By the use of this invention, the use of a liner is eliminated, as it is not necessary to case the well above the same.

It is thought from the foregoing description that the advantages and novel features of my invention will be readily apparent.

It is to be understood that I may make changes in the construction and in the combination and arrangement of the several parts, provided that such changes fall within the scope of the appended claim.

What I claim is In combination with a casing and an extension tube of smaller diameter than the casing, a shoe for connecting the casing with the extension and having a downwardly tapering bore, with internal grooves at its ends which are threaded, the upper groove receiving the lower end of the casing and the lower groove receiving the upper end of the extension tube whereby projections at the junction of the shoe with the casing and extension tube are eliminated, the lower end of the shoe being beveled to form cutting edge for engaging a shoulder formed in the well by the lower reduced part of the well.

In testimony whereof I aflix my signature.

OLIVER A. SEWELL. 

